High-field domain formation conditions in semiconductor multiple quantum well sequential resonant tunneling structures

We investigated the tunneling current-voltage (I-V) characteristics of Al0.3Ga0.7As/GaAs multiple quantum well (MQW) diodes sith various electron densities, N-s, and scattering rates: Gamma. Clear periodic negative differential resistances (NDRs) due to the formation of high-field domains were observed for the samples with low N-s and Gamma, while such NDRs were completely absent in the first plateau region of the I-V characteristics of the samples with high N-s and Gamma. It was found that such formation/destruction of the high-field domains in MQW diodes is controlled by the interplay of the tunneling rate and the electron supply functions between adjacent coupled quantum wells. The condition for the high-field domain formation is clarified as a function of N-s and Gamma.